Of course, the book is better. Jeff VanderMeer’s Annihilation is a lit-pulp marvel that expands the possibilities of what is possible within its genre, a heady, sweaty dip into not just enviro-cosmic horror but the inexplicable.
The book, the first entry in VanderMeer’s Southern Reach Trilogy, immerses readers in bio-impossibilities, in a landscape that pulses and mutates, in a mind bewildered by what it’s regarding, in a narrator we’re not sure we can trust.

She’s a biologist dispatched with a team of scientists into “Area X,” a swampy patch of Florida that has been seized by something they call “the Shimmer.” That’s an undulating scrim of light behind which flora and fauna have made baffling evolutionary leaps. No team that has been sent in has made it out.
Alex Garland’s Annihilation stars Natalie Portman, as a biologist among a team of scientists who keeps herself together the longest because she’s got a personal mystery to solve.
It’s a decent adaptation of Annihilation, as It Doesn’t Spoil the Book!

The book tells us what the biologist sees and does and thinks and wonders. And that’s it: We get no proper nouns identifying her or her team. We get no explanations about the source of all that the characters witness or suffer. So fecund, fearsome, beautiful and persuasive is VanderMeer’s imagination that the weirdness they encounter demands no clear explication — though the second and third books offer it, in some measure. (Those volumes are less sequels than re-examinations of Annihilation from new perspectives, something like how the later sections of The Sound and the Fury explicate Benjy Compson’s.)

Instead, his Annihilation offers something all too rare in stories of humans caught in alien environments: The environment and its mysteries are the sum of the work, and we’re spared the inevitable disappointment of explanation. The book thrills and terrifies because it never couches its horrors in backstory or pseudo-science

VanderMeer’s Annihilation might be unfilmable. The visions it stirred in my mind will, of course, look nothing like the ones it stirs in yours, and both beat most of what the creators of Paramount’s adaptation of the novel can conjure. I’m happy to report, then, that those creators don’t even try to get on-screen the peerless sequences set on a staircase in a tower or tunnel that forever ascends/descends into — well, seriously, read it and find out. That material demands a master filmmaker, an unlimited budget and a studio unafraid of the thought of audiences caught for full minutes in horrified ambiguity.